Thomas



UNITED s'rArEsz PATENT-OFFICE.,

THOMAS, STUBBLEFIELI), OF: COLUMBUS, GEORGIA.

'ATER-GAG-El IEOR,- STEAM-BOILERS..

Specification of.Letters Patent No.

To all whomz't mag/concern:

Beit known that I, THOMAS STUBBLEF' FIELD, of Columbus, :infthe county of Musko-f gee and State of.y Georgia,v have invent-ed certain new .and useful Improvements l in: Va'tenGages vfor Steam-Boilers,of. which: the` following is a full, clear, and exact del scription, reference being had to the. accompanying drawing, makingipart of thisspeci-- lication, in which-V FigureV 1, vrepresents 'an V:elevation iof `my improved gage, attached toa fragment ot.

a :steam.,boiler,` itsparts being intthe p0-` sitionfthey occupy when-:the avater in ,theg boiler is notv :too low. Fig.v 2,; represents -a similar viewwofwthe same, with itsparts in` the same position, butwi-th the casing-.in section, to show the detailsbf. theiinterior. of, the gage. Fig. 3,;represents aview similar to that shown inaiFigi, but; with'the` `parts in the positionthey occupy `when the :.water in the @boileris too lo`W,-the main=valve being; opened togive the alarm. Fig, 4, represents a `vertical secti'onoof the mainuvalve;I the secondary valvefbeing -shown'iwithin it'in7 elevation. Fig.A 5, represents. a transverse; section a through the main` `valve at the line meot Figa. Fig. 6, represents a topview ofthe valvesseparated fromthecase, andi Fig. 7,5represents a transverse sectionfof the valves at the line m of'r FigAe The alarm water-gageiin common-use in: steamnboilers, consists of a ,hollow,fglobu lar, metallic vessel, called a oat, to swim, on the Water within the boiler; and of a valve, to open land close -a duct for therescape of steam or water-from the boilerfto give an alarm whenthe waterfin the boiler isytoo low; thevalve andl float being so connectedy that; when the .water -is fhighathe` buoyancy of the yioat .will shutsthe valve; an'd when the :water is low, the weight of the'v oat will openrthefvalve.'l As, ingthisganfrangement, the ytloatihas to open the valve against the pressure fof ythe steam,"` the `aperey ture of the Vvalve must be small andathe.y float heavy.- The-smallnessof its aperture renders theavalvediable to be choked. bysmall-.pieces 1of :solid matter, and theigreat. weight lofi ythedioat. renders it liable pto give needless. alarmsby reason of ,theL momentumi generatedin` it by the incidentahmovementsv that areY 'communicatedto `it by-rthe, boiler,`

22,313, dated December 14, 1858i.

itself-,on by the. bubbling of the water within the.boiler; which momentum increases `the range and duration of `such incidental `movementsot the lioat, so asv to openthe valveand give an alarm while the water in :the boiler is still suiliciently high. Such great momentum alsotends to jam the valve in `its seat, or the lever for opening it, in its guides; and, thereby, to diminishI the certainty of an alarm accompanying a falli ofthe -water below .the safelevel.`

waterwinv a steam boiler, with a main valve lto` open and closea ductl for the=escape of- .ist-eam-or water from the boiler, and a small. secondary valve, between thefloat and the 'main valve, in suclrmanner that when the water:` in the. boiler falls below a givenJ height, the loat,by descending with it, will,

without; opposing the pressure of. the steam,

putthe malnwvalve in= such relations withl `the. yboiler-that then-pressure ofthe. steamr `thereinindependently of anyaid fromf-the itloat, will open thev main valve, to allow :steam or `waterto escape and give an alarm; ywhereby I am enabled to make the aperture 0f this valveas llarge-as is desirabletoavoid Idangeriotochoking, andato make a tloat asoA small and light that-neither itslweight incr the steam upon a large main valve, such as is used immy improved arrangement, a suddenuiopening ofthis valve would endanger ithe breaking of the gage; moreover if this valve were permitted to openzsuddenly the gage would be so extremely sensitive as to be constantly causing needless alarms tromz the momentary depression` of thefloat by the bursting of a bubble, or other like -accidentalcause.- I have, therefore, for. the purpose of avoiding these difficulties, provided means for. iretarding the sudden opening; of`

the .main valve, in any case; and of preventing itifroinbeing opened. at all, by a mo. mentarypdepression-iof the loat, while thegeneral-levelA of the water is .at a safe height.v This vbranch ;of "my improvement consistsin insulating-(in a chamber on the outside of'vthemain valve, and exposed to the air, ori-other cooling medium) a quan tity of steam sufficient to keep the valve shut against the pressure of the steam within theboiler; and permitting the 'steam thus insulated, to cool gradually, Aby radiation, until its elastic force is overcome by the inside pressure, when it will open gradually and quietly, without shock or jar, and with all the promptness required for giving timely notice of a deficiency of water in the boiler.

The gage shown in the drawing is of a form which adapts it to being applied to the top of a boiler, but it is obvious that, by simply changing the shape of the case and of the float lever, this gage could be applied to the sides or ends of the boiler as .well as to the top.

-This gage consists of a tubular case (A), closed at its upper end by a screw plug (B), and open at the lower end, which is inserted into the shell (C) of the boiler and secured 4there by screw nuts (D and E) one on the outside, the other on the inside of the boiler. On the inside of' the case (A) two valve seats (a and b) are formed, the aperture of the uppermost being somewhat the largest. The lower of these two seats is, for conven ience of construction, formed on the upper end of a tube (F) screwed into the lower end of the outer case. Thesel valve-seats are each. fitted with a puppet valve that opens upward, and the two valves are connected by a tubular stem (G) which causes them to open or shut simultaneously; for convenience of description, I shall call the two valves, thus united, (when I have occasion to speak of them collectively) the main valve. When these valves are shut the case (A) is divided into three compartments, the upper one (c) communicating, through the stem (G) of the main valve, with the lower compartment (CZ) and the interior of they' boiler; and the middle compartment v(e) being separated from the upper and lower compartments and the interior of the boiler. This middle compartment I call the escape duct or chamber; it communicates, through an opening in its side, with a pipe (I-I) leading to a steam whistle. In default of' a whistle, the escape chamber might open into the air, as the steam or water issuing from it would make a loud noise, and thereby give an alarm.

The opening through the stem of the main valve is contracted at the top and bottom, to form annular guides for the spindle (f) of a small secondary valve (g) fitted to the lower end of this opening. In order to make ample room for the passage of the steam by the spindle of the secondary valve into the chamber (c) the upper end of the opening (i) has several lateral'ducts branching out'from it; and the spindle, immediately above the secondary valve is fiuted, to leave passages between it and the sides of' the opening for the steam to pass through, as will more fully appear by reference to Fig. 7 of the drawings.

That end of the spindle (f) of the secondary valve which is below the valve, is jointed to a link-rod (I) which, in turn, is jointed to a lever (J) pivoted to a bracket (E) projecting downward from the nut (E) on that end of the case which projects into the boiler. The short arm of the lever (J) moves in a slot in another bracket (E2) eX- tending down from the same nut To the extremity of the long arm of the lever (J) a hollow globe of metal, hermetically sealed, is attached. This globe should be buoyant enough to float on the water in the boiler, and raise the long end of the lever l (J). The float is shown in Figs. 1, 2, and 3, Lvof the drawings, floating on the water in the ,boiler, which is represented by a series of parallel, interrupted lines,y and which in Figs. l and 2, is shown in abundance, while in-Fig. 3, it has fallen down to the lowest level at which it is safe to work, and therefore, has reached the point at which an alarm ought to be given. By observing the relative positionsof the several parts in Figs. 2 and 3, respectively,it will be seen that in the latter figure the alarm is being given, while in the other allis quiet.

So long as the water is high enough, the long arm of they lever is kept up, and the .short arm down; the latter, through the linlr(I), keeping the secondary valve (g) open; and, thereby, affording free access of the steam from the boiler to the chamber (c) above the. main. valve; so that the pressure on the u'pper valve (m) will tend to keep both the valves closed, and present the steam from passing into the escape duct (I-I) and giving an alarm; while the pressure on the lower valve (n) will tend to open both the valves and permit the steam to pass into the escape duct (H) and give an alarm; but since the upper valve is the largest it is obvious thatthe pressure upon it will preponderate, and keep the valves shut, and prevent any alarm, so long as the steam in the boiler has a free communication with the chamber above the upper valve; but when the water falls, and with it the float, to the level shown in Fig. 3, the short end of the lever will rise, and with it, the link (I) the secondary valve (g) will thus be closed, and shut off the steam in the boiler from the chamber (c) above the upper valve; the steam in the chamber, the moment the secondary valve is closed (being thereby insulated from the boiler) is rapidly cooled by radiation, which reduces, in a corresponding degree, its elastic force, which soon becomes less than that of the steam in the boiler against the lowest valve, when the latter begins to preponderate, andv opens to allow steam to escape into the duct (I-I) and give an alarm, which is maintained until the boiler is replenished with water; when the secondary valve is dropped, and an equilibrium of pressure restored between the chamber (c) and the` boiler. The main valve is shut by its own weight, and is kept closed by the prepondenance of pressure on its top, as before mentioned.

The secondary valve is arranged within the stem of the main valve for convenience, but it might be placed in Connection with a duct arranged, in any convenient way, in side or outside of the gage case; provided, itA connects the chamber (c) above the valves and the interior of the boiler in such manier that the steam in the chamber could be insulated from that in the boiler to permit the main valve to open, as before described.

I/Vhat I claim as my improvement in the alarm gage is,

l. The combination of a float, a secondary stantially as herein set forth.

In testimony whereof I have hereunto subscribed my name.

THOS. STUBBLEFIELD. Vitnesses:

HENRY BALDWIN, J r., WM. D. BALDWIN. 

